Semiconductor light source

ABSTRACT

A semiconductor light source for illuminating a physical space has been invented. In various embodiments of the invention, a semiconductor such as and LED chip, laser chip, LED chip array, laser array, an array of chips, or a VCSEL chip is mounted on a heat sink. The heat sink may have multiple panels for mounting chips in various orientations. The chips may be mounted directly to a primary heat sink which is in turn mounted to a multi-panel secondary heat sink. A TE cooler and air circulation may be provided to enhance heat dissipation. An AC/DC converter may be included in the light source fitting.

BACKGROUND OF INVENTION

[0001] The invention relates to the field of light sources andillumination devices. More particularly, the invention relates tosemiconductor light sources and illumination devices useful forproviding visible light in order to partially or fully illuminate aspace occupied by or viewed by humans, such as residential space,commercial space, outdoor space, the interior or exterior of a vehicle,etc.

[0002] In the prior art, light emitting diodes (“LED”s”) and othersemiconductor light sources were traditionally used for panel displays(such as laptop computer screens), signal lighting, and otherinstrumentation purposes. LED”s are desirable because they are a highefficiency light source that uses substantially less energy and createsless heat than typical prior art light sources such as incandescent andhalogen lights. Prior art semiconductor light sources have not beensuccessfully and economically used to illuminate physical spaces.Additionally, in the prior art, LED”s were typically individuallypackaged in a module, either with or without a focus dome on the module.Typical prior art LED modules lack high light intensity due to the sizeof the LED chips used. Further, arranging a sufficient number of priorart LED modules to generate high light intensity, such as use of astack, lamp or array, took an excessive amount of physical space andcreated unmanageable amounts of heat. Consequently, in the prior art,LED”s and other semiconductor light sources were not suitable forreplacing the traditional tungsten light bulbs.

[0003] U.S. Pat. No. 5,941,626 discloses a long light emitting apparatusthat uses a plurality of LED lamps (modules) connected in series. TheLED modules are spaced apart and appear to be intended for decorativeuse, such as on street lamp poles and on Christmas trees.

[0004] U.S. Pat. No. 5,160,200 discloses a wedge-base LED bulb housing.The patent depicts a plurality of separate LED modules electricallyconnected to a wedge base.

[0005] U.S. Pat. No. 4,675,575 discloses light-emitting diode assembliessuch as a mono-color or bi-color light string system. Each LED is in anenvelope with light conducting optical spheres for light transmissionand dispersion. The LED string system appears adapted for decorativeuse, such as for lighting Christmas trees.

[0006] A distinct need is felt in the prior art for a semiconductorlight source for use in illuminating a space with single color light inthe visible range and which can efficiently dissipate the heat that theyproduce. Presently, that application is served by incandescent andfluorescent lights which have high energy consumption, high heatgeneration, and short useful life compared to the invented semiconductorlight sources.

SUMMARY OF INVENTION

[0007] It is an object of some embodiments of the invention to provide asemiconductor light source capable of illuminating a space with visiblelight. Thes and other objects of various embodiments of the inventionwill become apparent to persons of ordinary skill in the art uponreading the specification, viewing the appended drawings, and readingthe claims.

BRIEF DESCRIPTION OF DRAWINGS

[0008]FIG. 1 depicts a semiconductor light source of one embodiment ofthe invention using a high power chip or array arrangement.

[0009]FIG. 2 depicts a semiconductor light source of one embodiment ofthe invention using high power surface mount LED chip modules or lamps.

[0010]FIG. 3a depicts an LED with an insulating substrate.

[0011]FIG. 3b depicts a detailed view of an LED structure on a sapphiresubstrate.

[0012]FIG. 3c depicts an LED with a conducting substrate.

[0013]FIG. 3d depicts a detailed view of an LED structure on a sapphiresubstrate.

[0014]FIG. 3e depicts a VCSEL chip on an insulating substrate.

[0015]FIG. 3f depicts a detailed view of a VCSEL chip on a insulativesubstrate.

[0016]FIG. 3g depicts a VCSEL chip on a conductive substrate.

[0017]FIG. 3h depicts a detailed view of a VCSEL chip in a conductivesubstrate.

[0018]FIG. 4a depicts a top view of an LED array on a single chip withan insulating substrate.

[0019]FIG. 4b depicts a top view of an LED array on a single chip with aconductive substrate.

[0020]FIG. 4c depicts a top view of a VCSEL array on a single chip withan insulating substrate.

[0021]FIG. 4d depicts a top view of a VCSEL array on a single chip witha conductive substrate.

[0022]FIG. 5a depicts a semiconductor chip of the invention that emitssingle color light using a conversion layer.

[0023]FIG. 5b depicts a semiconductor chip of the invention that emitssingle color light using a phosphor coating.

[0024]FIG. 6 depicts a cross sectional view of a heat sink of theinvention using a fan and TE cooler to circulate air and remove heat.

[0025]FIG. 7a depicts a single chip or single array chip package.

[0026]FIG. 7b depicts a multiple chip package.

[0027]FIG. 8a depicts a chip package with phosphor covering on thesemiconductor.

[0028]FIG. 8b depicts a chip package with a uniform phosphor coating.

[0029]FIG. 9 depicts a high power LED package.

[0030]FIG. 10 depicts an LED or laser light source located in a lightenclosure having a phosphor coating.

[0031]FIG. 11 depicts a power supply module with fitting for a lightsource of the invention.

DETAILED DESCRIPTION

[0032] Referring to FIG. 1, one embodiment of the invention is depicted.In this embodiment of the invention, a semiconductor light source 100 isdepicted. The light source 100 includes a traditional bulb-shapedenclosure 101. The enclosure 101 may be of any desired shape, includingspherical, cylindrical, elliptical, domed, square, n-sided where n is aninteger, or otherwise. The enclosure may be made from any desired lighttransparent or translucent materials, including glass, plastic,polycarbonate, and other light transparent materials.

[0033] The enclosure 101 has an exterior surface 101 a and an interiorsurface 101 b. The exterior surface 101 a may be smooth and glossy,matte, or another finish or texture. The exterior surface 110 a may becoated or painted with desired materials. The interior surface 101 b mayoptionally include an appropriate coating, such as a luminous powdercoating. Examples of luminous powder coating that may be used in theinvention include YAG:Ce or other phosphor powders or coatings. Forexample, if the light source uses blue LED”s to generate light, but itis desired to illuminate a room with white light, the interior surface101 b maybe covered with a phosphor coating to convert blue light intowhite light. Any wavelength-modifying coating such as phosphor oranother coating may be used. In some preferred embodiments of theinvention, it is intended to convert light emitted by a semiconductorchip in the wavelength range of about 200 to about 700 nm. to whitelight.

[0034] The enclosure 101 encloses an interior volume 102 which may be avacuum, or may contain a gas such as ordinary air, an inert gas such asargon or nitrogen, or any other desired gas. In some embodiments of theinvention, a gas will be included within the interior volume 102 for thepurpose of avoiding oxidation of the heat sink and the semiconductor.

[0035] The enclosure 101 may be mounted to a support 105. The support105 may be a separate component or may be integral with the base 103.The base 103 may be configured as a fitting or connector for use in adesired light socket, such as a traditional light socket. In such case,the base 103 would also include electrodes 103 a and 103 b for makingelectrical connection with a power source.

[0036] Located within the interior volume 102 is at least one heat sink104. The heat sink 104 may be of any desired shape, depending on theapplication. As depicted, the heat sink 104 has a generally flat orplanar top 104 a, and a plurality of generally flat or planar panels orcompartment 104 b, 104 c, 104 d, 104 e, 104 f, 104 g, 104 h, 104 i, etc.each of which may host a single or an array of semiconductor devicescapable of producing light. The heat sink 104 may be shaped otherwise,with curved or rounded sides.

[0037] If the heat sink 104 may be mounted on a support 105, the support105 may be designed in order to place the heat sink in the mostdesirable position within the interior volume 102 so that semiconductorslocated on the heat sink may emit ight that will be transmitted in adiffuse or focused pattern through the enclosure 101.

[0038] Mounted on the heat sink 104 are at least one semiconductordevice 106. The semiconductor device(s) 106 may be arranged in thisembodiment of the invention to transmit light in all directions exceptthrough the base 103, or in a manner to direct light in a specificdirection. The semiconductor devices may be any semiconductor devicescapable of emitting light, such as LED”s, LED arrays, VCSEL”s, VCSELarrays, photon recycling devices that cause a monochromatic chip to emitwhite light, and others.

[0039] The semiconductor devices 106 are electrically connected to eachother via electrical connections 107. Lead wires 108 a and 108 b areused to provide the semiconductor devices 106 with electrical power. Asdesired, the heat sink may serve as a positive or negative electricalconnection for the semiconductor devices.

[0040] The heat sink 104 may be any material capable of conducting heataway from the semiconductor devices. Examples of suitable materialsinclude copper, aluminum, silicon carbide, boron nitride and othersknown to have a high coeffecient of thermal conductivity.

[0041] In order to provide suitable electrical power to thesemiconductor devices, an AC/DC converter (not shown in this fixture) isutilized. This will permit the invented semiconductor light source to bepowered by 110 V. or 220 V. AC power found in homes and businessesthroughout the world. The AC/DC converter may be located in the base 103or in another location.

[0042] In alternative embodiments of the invention, each semiconductordevice may have its own individual heat sink, or two or moresemiconductor devices may be located on the same heat sink. In someembodiments of the invention, the base may also serve as a heat sink,eliminating the need for a separate heat ink and thereby reducing cost.

[0043] Referring to FIG. 2, a semiconductor device 2220 in enclosure2201 can be arranged to accommodate high power surface LED”s. “Highpower”LED”s means that the light output from each LED module is greaterthan 40 milliwatts. “Surface mount”LED”s are LED”s mounted directly on aheat sink, or other surface, in contrast with traditional LED lampswhich have ordinary electrical leads for wiring and must be separatelyheld in place. High power surface mount LED”s are described in detaillater in this document.

[0044] When high power LED”s are used, all the components are the sameas in FIG. 1 except that a high power LED 2206 is used. It can be seenthat the LED”s 2206 are electrically connected with electricalconnectors 2207 and are located on a heat sink 2204. The heat sink 2204has a plurality of heat sink faces 2210, 2211 and 2212 which are eachgenerally planar and are arranged in angular orientation with each otherin order to cause light from the LED”s to be dispersed around a space tobe illuminated. The heat sink faces can be oriented with respect to eachother at any desired angle, but 45 degree angles are depicted in thefigure so that face 2210 is perpendicular to face 2212. A standard base2203 is provided.

[0045] Any of the semiconductor light sources described below and othersmay be used in embodiments of the invention.

[0046]FIG. 3a depicts an LED chip with an insulating substrate 201. Thesubstrate 202 may be an appropriate material on which a semiconductormay be grown, such as sapphire, gallium arsenide, silicon carbide,gallium phosphorous, gallium nitride and others. The substrate 202 willalso in this embodiment be electrically insulative. The semiconductormaterial 203 will emit light in all directions as indicated by arrows204 a, 204 b, 204 c and 204 d. Positive 205 a and negative 205 belectrodes are provided for powering the chip.

[0047]FIG. 3b depicts an example of epitaxial layer configuration forthe LED of FIG. 3a. A light emitting diode on an electrically insulativesubstrate 1200 is depicted. The LED includes an electrically insulativesubstrate such as sapphire 1201. The substrate serves as a carrier, pador platform on which to grow the chip”s epitaxial layers. The firstlayer placed on the substrate 1201 is a buffer layer 1202, in this casea GaN buffer layer. Use of a buffer layer reduces defects in the chipwhich would otherwise arise due to differences in material propertiesbetween the epitaxial layers and the substrate. Then a conductive layer1203 is provided, such as n-GaN. This layer acts as a connector for anegative electrode. Then a cladding layer 1204, such as n-AlGaN, isprovided. Cladding layers serve to confine the electrons as they jumpfrom a conduction band to valance and give up energy that converts tolight. An active layer 1205 p-InGaN is then provided where electronsjump from a conduction band to valance and emit energy which converts tolight. On the active layer 1205, another cladding layer 1206, such asp-AlGaN is provided that also serves to confine electrons. A contactlayer 1207 such as p+-GaN is provided that is doped for Ohmic contact.The contact layer 1207 has a positive electrode 1208 mounted on it, inthis case an electrode that has a mount side on the contact layer 1207that is Ni and an electrode face that is Au. A similar negativeelectrode is provide on a shelf of the first cladding layer 1203.

[0048]FIG. 3c depicts an LED with a conducting substrate 210. Thesubstrate 211 must be an electrically conductive material on which asemiconductor ship may be grown, such as gallium arsenide, siliconcarbide, gallium phosphorous, gallium nitride and others. A portion ofthe substrate 212 will serve as an electrode for powering the chip, inthis case a negative electrode. The semiconductor material 213 will emitlight in all directions as indicated by arrows 214 a, 214 b, 214 c and214 d. A positive electrode 215 is provided, and the base 240 of thesubstrate 211 acts as a negative electrode. The base 240 is made of anyconductive metal such as Au, Au/Ce, An/Zn and others.

[0049]FIG. 3d depicts epitaxial layer configuration for the LED of FIG.3c. A light emitting diode grown on an electrically conductive substrate1210 is depicted. The LED includes an electrically conductive substratesuch as SiC 1212. The substrate serves as a carrier, pad or platform onwhich to grow the chip”s epitaxial layers, and as a negative electrodein the chip. The first layer placed on the substrate 1212 is a bufferlayer 1213, in this case a GaN buffer layer. Next, a cladding layer 1214is provided, such as n-GaN. An active layer 1215 p-InGaN is providedwhere energy is converted to light. On the active layer 1215, anothercladding layer 1216, such as p-AlGaN is provided. A contact layer 1217such as p+-GaN that has a positive electrode 1218 mounted on it. Anegative electrode 1211 is provided at the base of the chip.

[0050]FIG. 3e depicts a VCSEL chip on an insulating substrate 220. Thesubstrate 221 has a volume of semiconductor material 222 on it. Positiveelectrodes 223 a and 223 b and negative electrodes 224 are provided forpowering the chip, and light is emitted from the chip in directionsgenerally indicated by arrows 225 a and 225 b.

[0051]FIG. 3f depicts epitaxial layer configuration of the VCSEL chip ofFIG. 3e with an electrically insulative substrate 1220. The chip 1220includes a substrate 1221 that has electrically insulative propertiessuch as sapphire. On top of the substrate 1221 there is a buffer layer1222 such as GaN followed by a cladding layer and contact layer 1223such as n-GaN. The cladding layer 1223 includes a negative electrode1232 c. Next, there is another cladding layer nGaInN 1224. A reflectivelayer AlN/AlGaN MQW (multiple quantum wells) 1225 is provided. Acladding layer 1226 n-AlGaN is interposed between the reflective layer1225 and the active layer 1227 GaInN MQW. The active layer 1227 isfollowed by another cladding layer p-AlGaN 1228 which is followed by asecond reflective layer 1229 AlN/AlGaN MQW. Light emitted from theactive layer reflects between the two reflective layers until it reachesan appropriate energy level and then lases, emitting a laser beam oflight. The second reflective layer 1229 is followed by a cladding layerp AlGaN 1230 and a contact layer p+-GaN 1231. The contact layer may bering-shaped with a window opening 1233 and has one or more positiveelectrodes 1232 a and 1232 b which are contact areas. The negat veelectrode is created on the n-GaN layer.

[0052]FIG. 3g depicts a VCSEL chip on a conductive substrate 230. Thesubstrate 231 has a volume of semiconductor material 232 on it. Positiveelectrodes 233 a and 233 b are provided for powering the chip, and lightis emitted from the chip in directions generally indicated by arrows 235a and 235 b. The base 236 of the substrate 231 serves as a negativeelectrode.

[0053]FIG. 3h depicts epitaxial layer configuration of a VCSEL chip withan electrically conductive substrate 1239 such as that of FIG. 3g. Thechip 1239 includes a substrate 1241 that has electrically conductiveproperties such as SiC. The underside of the substrate 1241 has anelectrode 1240. On top of the substrate 1241 there is a buffer layer1242 such as GaN followed by a cladding layer 1243 such as n-GaN. Next,there is another cladding layer NGaInN 1244. A reflective layer usingAlN/AlGaN MQW (multiple quantum wells) 1245 is then provided. A claddinglayer 1246 n-AlGaN is interposed between the first reflective layer 1245and the active layer 1247 GaInN MQW. The active layer 1247 is followedby another cladding layer p-AlGaN 1248 which is followed by a secondreflective layer 1429 AlN/AlGaN MQW. The second reflective layer 1249 isfollowed by a cladding layer p AlGaN 1250 and a contact layer p+-GaN1251. The contact layer may have one or more positive electrodes 1252 aand 1252 b mounted on it.

[0054]FIG. 4a depicts a top view of an LED array on a single chip with asize a×b on an insulating substrate 301. Each of sizes a and b isgreater than 300 micro meters. Semiconductor materials 302 are locatedon an electrically insulative substrate (not shown). Positive 303 andnegative 304 pads are provided, each in electrical connection with itsrespective metal strip 305 and 306 arranged in a row and columnformation (8 columns shown) to create the array and power the chip. Thisenables the LED to emit high power light from a single chip.

[0055]FIG. 4b depicts a top view of an LED array on a single chip with asize a×b on a conductive substrate 310. Each of sizes a and b is greaterthan 300 micro meters. Semiconductor materials 312 are located on anelectrically conductive substrate (not shown). Positive pad 313 isprovided in electrical connection with a metal strip 315 arranged in anarray formation to power the chip. The substrate 310 serves as thenegative electrode in the embodiment depicted.

[0056]FIG. 4c depicts a top view of a VCSEL array on a single chip witha size a×b on an insulating substrate 320. Each of sizes a and b isgreater than 300 micro meters. The chip 320 includes an electricallyinsulative substrate (not shown) on which a semiconductor material 332is located covered by a panel 333. The panel 333 may be an appropriateconductive material such as Au/Ce, Au/Zn and others. The panel 333 has aplurality of windows 334 in it to permit light produced by thesemiconductor material 332 to be emitted for use. The panel 333 iselectrically connected to conductive metal strip 340 and to an electrodepad 335. A negative electrode pad 336 is also provided in electricalconduction with a metal strip 337 to power the chip.

[0057]FIG. 4d depicts a top view of a VCSEL array on a single chip witha dimension a×b on a conductive substrate 340. Each of sizes a and b isgreater than 300 micro meters. It includes a conductive substrate (notshown) on which a semiconductor material 341 is located. A conductivepanel 342 overlays the semiconductor material 341. A plurality ofwindows 343 are provided in the panel 342 to allow light produced by thechip to escape for us. A positive electrode pad 344 is provided which inconjunction with the electrically conductive substrate serving as anegative electrode power the chip. A negative electrode is provided onthe bottom of the chip 340.

[0058]FIGS. 5a and 5 b depict a semiconductor chip system that emitswhite light. In FIG. 5a, there is a GaN based semiconductor chip 2000depicted. It includes a GaN system 5001 built on an insulative sapphiresubstrate 5002 capable of emitting blue light, the general structure ofwhich is known in the prior art. A light conversion layer 5003 such asAlGaInP (aluminum gallium indium phosphate) adjacent the sapphire layer5002 opposite the GaN system 5001. Light emitted from the GaN systemwill travel through the sapphire layer 5002, through the AlGaInP 5003 toexit the chip system. Some of the blue light will be absorbed by theAlGaInP to emit yellow light, and some of the blue light will betransmitted through the AlGaInP. The combination of blue and yellowlight emitted by the chip according to arrows 5004 a, 5004 b and 5004 cwill appear as white light to human eyes. Electrodes 5005 and 5006 areprovided for electrical connection. Referring to FIG. 5b, the chip 2000is depicted following application of an exterior light conversioncoating or layer 5007 such as phosphor. Light which exits through thephosphor such as 5004 a will be converted in wavelength to white, makinga useful light for illuminating physical spaces. A coating or layer toconvert monochromatic light to white light may include phosphor powder,YAG/Ce and others. Such a coating or layer may be applied by the methodsof brush coating, flow coating and evaporative coating.

[0059]FIG. 6 depicts a cross sectional view of a heat sink of theinvention 401. As depicted in this embodiment, a plurality ofsemiconductor chips or high power LED”s 402 capable of emitting lightare mounted in a well of the heat sink material 403 (surface mounting).The mounting of the chips or high power LED”s may be achieved by use ofa heat-conductive adhesive 404, or by brazing or mechanical fixation.The heat sink material 403 is of sufficient thickness to conduct heataway from the chips 402 and keep the chips cool. Located within the heatsink 403, a layer or lining of thermal electric material 405 may beinstalled. Thermal electric (“TE”) material experiences a reduction intemperature when voltage is applied to it. By applying a voltage to theTE material 405, its temperature can be lowered and heat can be drawnfrom the heat sink material 403 that in turn is drawing heat away fromthe chips 402. The TE material may line an air chamber 406. The airchamber is open at its entrance 406 a and at its exit 406 b. A fan 407may be placed in or near the air chamber 406 in order to cause air 408to travel in the entrance 406 a, through the air chamber 406 past the TEmaterial 405 and out of the exit 406 b, carrying heat with it. Such asystem will increase efficiency of heat dissipation from the chips 402.At the bottom of the heat sink, a fitting or connector may be providedthat is threaded 409 a and has an electrode 409 b for installation intoa traditional light socket.

[0060]FIG. 7a depicts a single chip or single array chip surface mountpackage 501. It includes a semiconductor chip or array 502 capable ofemitting light mounted in a well 503 of a heat sink 504. The well 503 isprovided with reflective sides to that light emitted from the sides ofthe chip or array 502 is reflected out of the well in order to provideuseful illumination and to minimize heat buildup. The chip or array 502may be mounted in the well 503 by use of a heat conductive adhesive 505or by brazing or mechanical fixation. The heat conductive adhesive mayalso be used as a reflector to reflect light from the substrate in thedirection of arrows 509 a and 509 b. Connection blocks 507 and 508 maybe mounted on the heat sink 504 in order to facilitate electricalconnection of the chip 502. Light exits the chip as indicated by arrows509 a, 509 b and 509 c.

[0061]FIG. 7b depicts a multiple chip package 520. It includes multiplewells 521 a, 521 b and 521 c on a heat sink 522 in which multiple chipsor arrays 523 a, 523 b and 523 c are located. Connection blocks 524 a,524 b, 524 c and 524 d are provided with lead wires 525 a, 525 b, 525 c,525 d and 525 f in order to electrically power the chips or arrays.

[0062]FIG. 8a depicts a chip package with phosphor covering 601. Thepackage includes a heat sink 602 in which a well is located 603 forreceiving a chip or array 604. Connection blocks 605 a and 605 b andlead wires 606 a and 606 b may be used to electrically power the chip orarray 604. A thickness of phosphor 607 may be placed over the chip orarray 604 in order to convert single wavelength light emitted from thechip or array into multiple wavelength white light useful forillumination of spaces used by humans. FIG. 8 b depicts another phosphorcoated chip package 6000. It includes a heat sink 6001 on which a lightemitting chip 6002 is mounted in a receptacle 6005 on the heat sink. Thechip 6002 does not fill the entirety of the receptacle 6005 so atransparent filler 6003 of a material transparent to the wavelength oflight emitted by the chip 6002 is provided. Some transparent materialswhich may be used include epoxy, plastic and others. On the face of thechip 6002 opposite the heat sink 6001 a wavelength conversion coating orlayer 6004 is provided to convert the light emitted by the chip to whitelight. A phosphor coating is preferred.

[0063]FIG. 9 depicts a high power surface mount LED package 901 usefulin the invention. The LED package 901 includes a heat sink 902 formedfrom a material which can dissipate heat. A well 904 is formed in theheat sink in order to accept an LED, laser diode or semiconductor chiparray 903 therein. The well 904 has walls 905 for reflecting light 906 aand 906 b emitted by the chip(s) 903. An optional phosphor coating 907is provided over the chip(s) to convert light emitted by the chip(s) towhite light. The chip(s) 903 are secured to the heat sink 903 by use ofadhesive 908. The adhesive 908 may be heat conductive to aid intransmission of heat from the chips to the heat sink, and it may havelight reflective properties to aid in reflection of light from the chipsin the direction of arrows 906 a and 906 b in a usable direction.Reflection of light by the well and the adhesive provides more efficientlight output than would otherwise be achieved. Connection blocks 909 aand 909 b are provided for forming electrical connection with diodes 910a and 910 b. A focus dome, lens, or cover 910 is provided that istransparent to the light being emitted. The focus dome may have thecharacteristic of serving to focus light being emitted from the chips inorder to create a substantially coherent beam of usable light.

[0064]FIG. 10 depicts a light source of the invention 1001 having an LEDor laser light source 1002 located in an enclosure 1003. The enclosuremay be any appropriate shape. The depicted shape is that of a bulb, butflat, arcuate, rounded or other shapes may be used depending on theapplication. The enclosure 1003 may be glass, plastic, polycarbonate orany other material that is substantially transparent to the light to beemitted. The enclosure 1003 has an exterior surface 1003 a and aninterior surface 1003 b. The enclosure serves as a protector of thelight source 1002 and it may be designed to diffuse light. The interiorsurface 1003 b of the enclosure may have a coating or layer 1004 whichserves to alter properties of the light emitted from the light source1002. For example, if light from the light source 1002 is singlewavelength, then the light-altering coating 1004 may be phosphorouswhich will turn the monochromatic light into white light. Other coatingsmay be used as desired to alter the light in other ways.

[0065]FIG. 11 depicts a power supply module 701 for a light source ofthe invention. The power supply module 701 includes a fitting orconnector 702 with electrodes 703 and 704 for receiving AC electricalinput from a traditional light bulb socket. An AC/DC converter 705 isprovided to convert AC power from standard building wiring into DC powerusable by the semiconductor chips of the invention. Electrical leadwires 706 a and 706 b are provided for electrical connection to thechips to power the light source, and electrical lead wires 707 a and 707b are provided to provide power for the cooling fan TE cooler. Thecoating may be applied on the interior or exterior of the enclosure, orboth.

[0066] Examples of some heat sink materials which may be used in theinvention include copper, aluminum, silicon carbide, boron nitridenatural diamond, monocrystalline diamond, polycrystalline diamond,polycrystalline diamond compacts, diamond deposited through chemicalvapor deposition and diamond deposited through physical vapordeposition. Any materials with adequate heat conductance can be used.

[0067] Examples of heat conductive adhesives which may be used aresilver based epoxy, other epoxies, and other adhesives with a heatconductive quality. In order to perform a heat conductive function, itis important that the adhesive possess the following characteristics:(i) strong bonding between the materials being bonded, (ii) adequateheat conductance, (iii) electrically insulative or electricallyconductive as desired, and (iv) light reflective as desired. Examples oflight reflective adhesives which may be used include silver and aluminumbased epoxy.

[0068] Examples of substrates on which the semiconductors used in theinvention may be grown include Si, GaAs, GaN, InP, sapphire, SiC, GaSb,InAs and others. These may be used for both electrically insulative andelectrically conductive substrates.

[0069] Materials which may be used to used as a thermoelectric cooler inthe invention include known semiconductor junction devices.

[0070] It will be preferred that the semiconductor light source of theinvention will emit light in the wavelength range of 200 to 700 in orderto be useful for illumination of a physical space used by humans.

[0071] Heat sinks used in this invention can be of a variety of shapesand dimensions, such as those depicted in the drawings or any otherswhich are useful for the structure of the particular light source beingconstructed.

[0072] Any of the foregoing, including combinations thereof, and othersemiconductors, materials and components may be used in the inventedlight sources.

[0073] While the present invention has been described and illustrated inconjunction with a number of specific embodiments, those skilled in theart will appreciate that variations and modifications may be madewithout departing from the principles of the invention as hereinillustrated, as described and claimed. The present invention may beembodied in other specific forms without departing from its spirit oressential characteristics. The described embodiments are considered inall respects to be illustrative and not restrictive. The scope of theinvention is, therefore, indicated by the appended claims, rather thanby the foregoing description. All changes which come within the meaningand range of equivalence of the claims are to be embraced within theirscope.

1. A semiconductor light source for emitting light to illuminate a spaceused by humans, the semiconductor light source comprising: an enclosure,said enclosure being fabricated from a material substantiallytransparent to white light, a base to which said enclosure is mounted,an interior volume within said enclosure, a secondary heat sink locatedin said interior volume, said secondary heat sink being capable ofdrawing heat from one or more semiconductors devices, a plurality ofprimary heat sinks mounted on said secondary heat sink, each of saidprimary heat sinks being smaller than said secondary heat sink, asemiconductor chip capable of emitting light mounted on one of saidprimary heat sinks, said semiconductor chip being capable of emittingmonochromatic light, said semiconductor chip being selected from thegroup consisting of light emitting diodes, light emitting diode arrays,laser chips, and VCSEL chips, said chip including a substrate on whichepitaxial layers are grown, a buffer layer located on said substrate,said buffer layer serving to mitigate differences in material propertiesbetween said substrate and other epitaxial layers, a first claddinglayer serving to confine electron movement within the chip, said firstcladding layer being adjacent said buffer layer, an active layer, saidactive layer emitting light when electrons jump to a valance state, asecond cladding layer, said second cladding layer positioned so thatsaid active layer lies between cladding layers, and a contact layer onwhich an electron may be mounted for powering said chip, and a coatingfor converting monochromatic light emitted by said chip to white light.2. A device as recited in claim 1 further comprising a first and asecond reflective layers, each of said first and second reflectivelayers being located on opposite sides of said active layer, saidreflective layers serving to reflect light emitted by said active layer.3. A device as recited in claim 2 wherein said reflective layers includemultiple quantum wells.
 4. A device as recited in claim 1 wherein saidsubstrate is selected from the group consisting of Si, GaAs, GaN, InP,sapphire, SiC, GaSb, InAs.
 5. A device as recited in claim 1 whereinsaid substrate is electrically conductive.
 6. A device as recited inclaim 1 wherein said substrate is electrically insulative.
 7. A deviceas recited in claim 1 wherein at least one of said epitaxial layersincludes a material selected from the group consisting of GaN, AlGaN,AlN, AlGaN, GaInN, and GaInN.
 8. A device as recited in claim 1 furthercomprising a phosphor coating on said chip.
 9. A device as recited inclaim 1 further comprising a power module for powering the light source,said power module including a fitting for installation in a traditionallight bulb socket and an AC/DC converter for converting AC power fromtraditional building wiring to DC power usable by a semiconductordevices.
 10. A device as recited in claim 1 wherein at least one of saidheat sink includes a material selected from the group consisting ofinclude copper, aluminum, silicon carbide, boron nitride naturaldiamond, monocrystalline diamond, polycrystalline diamond,polycrystalline diamond compacts, diamond deposited through chemicalvapor deposition and diamond deposited through physical vapordeposition.
 11. A device as recited in claim 1 further comprising aquantity of heat conductive adhesive located between said chip and saidprimary heat sink and serving to conduct heat from said chip to saidprimary heat sink.
 12. A device as recited in claim 1 further comprisinga quantity of light reflective adhesive located between said chip andsaid primary heat sink.
 13. A semiconductor light source for emittinglight to illuminate a space used by humans, the semiconductor lightsource comprising: an enclosure, said enclosure being fabricated from amaterial substantially transparent to white light, a base to which saidenclosure is mounted, an interior volume within said enclosure, asecondary heat sink located in said interior volume, said secondary heatsink being capable of drawing heat from one or more semiconductorsdevices, a plurality of primary heat sinks mounted on said secondaryheat sink, each of said primary heat sinks being smaller than saidsecondary heat sink, a plurality of wells, said wells being located onsaid primary heat sinks and being sized to accommodate mounting of asemiconductor chip therein, a semiconductor chip capable of emittinglight mounted in one of said primary heat sink wells, said semiconductorchip being capable of emitting monochromatic light, a quantity ofadhesive serving to secure said chip to said primary heat sink, saidchip including a substrate on which epitaxial layers are grown, a bufferlayer located on said substrate, said buffer layer serving to mitigatedifferences in material properties between said substrate and otherepitaxial layers, a first cladding layer serving to confine electronmovement within the chip, said first cladding layer being adjacent saidbuffer layer, an active layer, said active layer emitting light whenelectrons jump to a valance state, a second cladding layer, said secondcladding layer positioned so that said active layer lies betweencladding layers, and a contact layer on which an electron may be mountedfor powering said chip, and a coating for converting monochromatic lightemitted by said chip to white light.
 14. A device as recited in claim 13further comprising a first and a second reflective layers, each of saidfirst and second reflective layers being located on opposite sides ofsaid active layer, said reflective layers serving to reflect lightemitted by said active layer.
 15. A device as recited in claim 14wherein said reflective layers include multiple quantum wells.
 16. Adevice as recited in claim 13 wherein said substrate is selected fromthe group consisting of Si, GaAs, GaN, InP, sapphire, SiC, GaSb, InAs.17. A device as recited in claim 13 wherein said substrate iselectrically conductive.
 18. A device as recited in claim 13 whereinsaid substrate is electrically insulative.
 19. A device as recited inclaim 13 wherein at least one of said epitaxial layers includes amaterial selected from the group consisting of GaN, AlGaN, AlN, AlGaN,GaInN, and GaInN.
 20. A device as recited in claim 13 further comprisinga phosphor coating on said chip.
 21. A device as recited in claim 13further comprising a power module for powering the light source, saidpower module including a fitting for installation in a traditional lightbulb socket and an AC/DC converter for converting AC power fromtraditional building wiring to DC power usable by a semiconductordevices.
 22. A device as recited in claim 13 wherein at least one ofsaid heat sink includes a material selected from the group consisting ofinclude copper, aluminum, silicon carbide, boron nitride naturaldiamond, monocrystalline diamond, polycrystalline diamond,polycrystalline diamond compacts, diamond deposited through chemicalvapor deposition and diamond deposited through physical vapordeposition.
 23. A device as recited in claim 13 further comprising aquantity of heat conductive adhesive located between said chip and saidprimary heat sink and serving to conduct heat from said chip to saidprimary heat sink.
 24. A device as recited in claim 13 furthercomprising a quantity of light reflective adhesive located between saidchip and said primary heat sink.
 25. A device as recited in claim 13further comprising a cover over said chip in said well.
 26. A device asrecited in claim 13 further comprising a coating over said chip in saidwell.
 27. A device as recited in claim 13 further comprising atransparent material located in said well and covering said chip, saidtransparent material being capable of converting monochromatic lightemitted by said chip to white light.